The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
A power metering system can be used in, for example, a panel breaker box of a building, to determine and report power collectively consumed by loads within the building. The loads may be distributed in the building and thus may be remotely located away from the panel breaker box. The power metering system may include for each phase of alternating current (AC) utility power a voltage sensing module and a current sensing module. The voltage sensing modules and current sensing modules may be connected to a monitoring module. Each of the voltage sensing modules may be connected to respective bus bars via terminals and detect a voltage between a pair of the bus bars. A first bus bar in the pair of bus bars may receive, for example, a single phase of AC utility power. A second bus bar in the pair of bus bars may be at, for example, a neutral potential.
The current sensing modules may be connected via wires to respective current transformers. Each of the current transformers may be on one of the bus bars receiving the AC utility power and detect current drawn collectively by the loads of the building. The current transformer of a current sensing module is located in close proximity to the terminals at which a corresponding voltage is detected. This minimizes distance between the terminals and the current transformer and can minimize time lag between when voltage and current measurements are taken. Close proximity of the terminals and the current transformer also minimizes the amount of power losses between the terminals and the current transformer to allow for an accurate power calculation.
The voltage sensing modules and the current sensing modules may respectively signal condition the detected voltages and currents prior to providing the voltages and currents to the monitoring module. The monitoring module may then determine power drawn collectively by the loads for each of the bus bars receiving AC utility power based on the signal conditioned voltages and currents. The power may be indicated via, for example, a display. The monitoring module may perform for each of the bus bars receiving AC utility power a predetermined number (e.g., 100) of power calculations per cycle of the AC utility power.